NEW YORK, June 13 -- It took three letters to start an international incident. Selena Gomez typed "lol" under an Instagram post, and within a day she was issuing the kind of statement usually reserved for people who have actually said something.

The post belonged to MTV, a carousel of celebrities at Madison Square Garden for Game 4 of the NBA Finals on June 10, the night the Knicks erased a 29-point deficit for the biggest comeback in Finals history. The first slide showed Taylor Swift mid-celebration, hugging "Law & Order" star Mariska Hargitay and leaping alongside Este Haim, all of it captured during the kind of night Hargitay later called one of the greatest of her life. Gomez, scrolling like everyone else, left her three letters and...